Shield for engine mufflers associated with sawing machines



March 13, 1956 s. s. STIERS SHIELD FOR ENGINE MUFFLERS ASSOCIATED WITHSAWING MACHINES 2 Sheets-Sheet 1 Filed Feb. 24, 1955 FIG].

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INVENTOR Sidneyfi. Stiers 2 ATTORNEKZ March 13, 1956 s. s. STIERS SHIELDFOR ENGINE MUFFLERS ASSOCIATED WITH SAWING MACHINES 2 Sheets-Sheet 2Filed Feb. 24, 1953 INVENTOR 5i (1')?5/5- .S' tiers ATTORNEY;

United States Patent SHIELD FOR ENGINE MUFFLERS ASSOCIATED WITH SAWIN GMACHINES Sidney S. Stiers, Lowell, Greg. Application February 24, 1953,Serial No. 338,183 1 Claim. (Cl. 60-31) The present invention relates toa muflller attachment for use with engines and, more particularly, to ashield or guard arranged to be associated with the muflier of aninternal combustion engine or the like.

Heretofore, gas motor chain power saws for cutting timber such as treesand logs, have created a serious fire hazard and have been responsiblefor a large number of forest fires, due to the fact that the mufilers onsuch motor saws soon become overheated with the result that anyinflammable material, such as sawdust and the like that comes in contactwith the mufller are quickly ignited.

Accordingly, an important object of the present invention consists inproviding simple, eflicient and inexpensive means in the form of ashield having a tubular portion enclosing the muffler and spacedtherefrom to provide a cold air circulating passage that extendscompletely around the mulfier. Additionally, the inner end of thetubular portion of the shield is preferably formed on one side with aradially and outwardly extending flange that constitutes an air scoop.The opposite side of the tubular member adjacent the inner end thereofis provided with a transversely disposed air slot which coacts with theair scoop to introduce cold air into the passage between the mufller andthe shield, so as to cause the temperature of the exhaust gases passingthrough the muflier to be cooled to such an extent that any inflamrnableobject, such as sawdust and the like, which may accidentally come incontact with the shield, will not catch fire. Thus, it will be seen thatmeans which can be quickly and easily installed are provided forreducing the intense heat of the exhaust gases as they are dischargedfrom the mufller so as to reduce the danger of forest fires and thelike, previously caused by the use of motor-driven power saws of thistype.

Another object consists in associating with the shield and the flywheelof an air cooled motor, means for con ducting a portion of the air usedto cool the motor through the shield, and mixing this air with outsideair prior to its passage through the shield in order to assist inreducing the heat transferred to the shield by the exhaust gases passingthrough the muffier.

Other objects and advantages of the invention will become apparent fromthe following description when taken in conjunction with theaccompanying claim and drawings.

Referring to the drawings, in which is disclosed for illustrativepurposes, one form the invention may assume,

Figure 1 is an elevational view of a stationary motor provided with amuffler shield constructed in accordance with the present invention, andshown operatively associated with an endless chain sawing machine.

Figure 2 is a plan View of the sawing machine assembly shown in Figure1.

Figure 3 is a detailed side view showing the shield enclosing themuflier and attached thereto, and with parts in section for clearness ofillustration.

Figure 4 is a right-hand end view of Figure 3 with the muffler removed.

Figure 5 is a bottom plan view of Figure 3.

Figure 6 is a left-hand end view of Figure 5, and

Figure 7 is a plan view of Figure 3.

Referring to the drawings, 10 indicates a stationary motor which isshown associated with a sawing ma chine 11, of any well-known type. Theengine 10 is enclosed in a casing 12 (Figure 2) and may have an offsetinner portion 13 in which is rotatably mounted the flywheel 14 that isoperatively connected to the drive shaft of the engine, not shown. Theouter end 15 of the portion 13 of the casing 12 is preferably providedwith a reticulated screen or opening 16 for introducing cold air intothe casing in order to provide means for cooling the engine or motorduring the operation of the machine. The sawing machine 11 is providedwith the usual endless chain 17 which carries the cutting teeth 18 andmay be operatively connected to the drive shaft of the engine in theusual well known manner. The front 19 of the casing 12 on one side ofthe sawing machine 11 has an outwardly flared wall 20 terminating in asubstantially elliptical-shaped end plate 21 provided with horizonttllyspaced exhaust openings 22 (Fig. 5). An elliptical-shaped muffler 23 hasat its inner end a plate 24 similar in shape to the plate 21 and isprovided with spaced openings 34 which register with the exhaustopenings 22. The muffler is firmly secured to the engine 20 by theretaining bolts 25 which extend through aligned openings 25' (Fig. 4) inthe end plates 21 and 24 respectively when the parts are assembled.Manifestly, the shape of the mufller and the end plates may be of anysuitable circular or non-circular configuration as the particularoperating conditions may require.

Due to the intense heat of the exhaust gases, as they discharge from themuffler, it will be seen that any inflammable material which mightaccidentally contact or collect on the mufller during the operation ofthe machine, would soon ignite and cause a serious fire hazard,particularly where the motor is used for sawing timber in the forest,such as the trunks of trees, logs, and the like. Accordingly, a guardattachment in the form of a shield 26, made of any suitable durablemetal or the like, is associated with the muffler 23. The shield 26preferably includes an elongated tubular portion or sleeve 27 opened atboth of its ends and having the major portion thereof of substantiallythe same configuration as the mufller. The inner or rear end 28 of thetubular member 27 has laterally and outwardly extending therefrom aflange 29 that projects from one side thereof and which is preferablycurved and shaped as shown in Figure 5, so as to extend substantiallyhalfway around the elliptical tubular portion 27 in order to constitutean air scoop for conducting cold air into the shield 26. The inner end28 of the shield opposite the air scoop 29 has a transversely disposedslot 30 (Fig. 7) that provides additional means for introducing air intothe tubular portion 27 so as to insure complete circulation of thecooling medium through the shield.

The shield 26 is connected to the mufiler 23 at only two spaced points31 (Fig. 7) in any suitable manner, such as by welding or the like 32,so as not to otherwise interfere with the introduction of cold air intothe tubu lar portion 27 of the shield through the scoop 29 and the slot38. The tubular portion 27 of the shield is larger than the muffler 23so as to provide a space or passage 33 completely around the mufller forconducting air from the inner end to the outer end of the shield whenthe parts are assembled.

The outer end portion 35 of the mufller 23 is laterally offset andextends outwardly and away from the sawing Mama.

machine 11, so as to conduct the exhaust gases away from the tree or logbeing cut. The end portion 35 may also be provided with a substantiallyelliptical plate 36 having transversely disposed louver openings 37 fordeflecting the exhaust gases outwardly and away from the sawing machine.The shield 26 'is also shaped or bent to provide an angulated outer endportion 38 simi 'lar in shape to the end portion 35 and spaced therefromto form a continuation of the air passage 33 so that the shield isopened throughout the length thereof for re- 2 tend beyond the offsetreduced side portion 10' of the casing 10 (Fig. 2) to a point adjacentbut spaced from the air scoop 29 so that the cold air forced into thecasing 10 has a portion thereof deflected so as to pass through thegrooves 4%, where a portion of this air discharges to the atmosphere.The remaining portion of the air discharges into the scoop 29 and drawswith it outside air which, as it circulates through the passage 33,coacts with the outside air introduced into the passage 33 through theslot 3 to flow completely around the mufiler 23 thus causing thetemperature of the exhaust gas passing through the mufiier to be cooledto such an extent that any inflammable object, such as sawdust or thelike, that might collect onthe shield, will not catch fire. Further, theshield or guard provides means that may be quickly installed on any typeof rnuifier for the purpose of greatly reducing the temperature of theexhaust gases as they are discharged into the atmosphere.

The stationary engine 10 may be supported by any suitable means such asthe frame assembly 41, in which the engine 10 and its associated partsare mounted, so as to be readily transported from place to place at aminimum expenditure of time, effort and cost. The stationary air cooledmotor I'll may be formed of one or more gas cylinders and while shownoperatively connected to an endless chain power saw, it will be manifestthat it may be used with equal efficiency with various other types ofengines. The shield 26 is preferably co-extensive in length with themuffler 23 and forms therewith the continuous or uninterrupted airpassage 33 that completely encloses the muffier so that the cold airpassing through the shield contacts a wide area of the muflier to reducethe heat of the exhaust gases passing therethrough.

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Thus it will be seen that an air cooled shield attachment is providedfor the muffiers of internal combustion engines that can be easilyinstalled and is readily accessible for inspection or repair. Further,the tubular shield constitutes eflicient means for preventing theignition of inflammable material such as s wdust and the like, whichmight accidentally contact or collect thereon. By reason of the novelassociation of the shield with the muffler and the engine, a constantflow of cold air is insured to be conducted between the mufiler and theshield so as to maintain the latter at a desired low temperature.

It will be understood that the form of the invention shown is merelyillustrative of a preferred embodiment and that such changes may be madeas come within the purview of the following claim.

i claim:

In combination with an air-cooled internal combustion engine having acasing provided on one side with vertically spaced fins for forminglongitudinal air passages, means for circulating air through saidpassages, a muffler communicating with the casing on one side thereoffor discharging exhaust gases from the engine, a shield having a tubularportion encircling the muffler and spaced therefrom to form an aircirculating passage, said tubular portion having an opened inner endprovided with a laterally and outwardly projecting flange spaced fromthe casing and constituting an air scoop positioned in front of andadjacent said fins for receiving air as it issues therefrom, said shieldadjacent its inner end and on the side opposite said air scoop having aslot for introducing outside air into said tubular portion, said mufflerhaving an angularly disposed outer end closed'by a plate provided withtransversely spaced louver openings, said tubular portion having anouter end bent to encircle the outer end of the mutiler and be spacedtherefrom to form a continuation of the air circulating'passage, andmeans con necting said shield to the casing so as not to interfere withthe passage of the air from the casing into the mufiler, the parts beingconstructed and arranged so that any inflammable object coming incontact with the shield is not ignited by the heat of the muflier.

References (Iited in the file of this patent UNITED STATES PATENTS867,271 Hofmann Oct. 1, 1907 917,081 Krygowski Apr. 6, 1909 1,132,391Ruttle Mar. 16, 1915 1,634,000 Smith June 28, 1927 2,138,001 Fluor, JrNov. 29, 1938 2,382,387 Alford Aug. 14, 1945 2,519,936 Sayre Aug. 22,1950

